Microwave-mediated ultrafast solid-state construction of O vacancies enriched cobalt oxide/nitrogen carbon aerogel toward efficient tetracycline degradation with peroxymonosulfate

A rapid microwave assisted carbonization of dicyandiamide and cobalt nitrate was developed for the first time to prepare cobalt oxide/nitrogen carbon aerogel materials, in which cobalt oxide species were uniformly loaded with the characteristics of multivalent Co species. Moreover, the rapid heating process introduced abundant oxygen vacancies and N containing heterocycles in Co@NC3A materials. The optimal Co@NC3A exhibited complete TC degradation within 10 min with a rate constant up to 0.8609 min−1 at 25 °C. Meanwhile, the Co@NC3A also had general applicability in various antibiotics and dyes degradation. Radical quenching experiment and EPR test revealed the coexistence of radical and non-radical activation process in Co@NC3A/PMS system. Multivalent Co species could activate PMS to facilitate the SO4•- and •OH production. In addition, 1O2 and direct electron transfer mediated non-radical pathways were accelerated with O vacancies and N containing heterocycle.